CASCADE TOWNSHIP, MI — An ambitious, controversial plan by Gerald R. Ford International Airport to stem the environmental impacts of its storm water runoff is being met with praise and skepticism alike.

The ongoing dispute over the millions of gallons of runoff pumped by Ford Airport into a nearby tributary that feeds the Thornapple River will add another chapter during a public meeting Thursday in Cascade Township.

Residents who live near that tributary, called Trout Creek, the Ada and Cascade River Associations and Ford Airport leaders will discuss the latest concerning the $19 million plan to reroute its storm water.

"I think it's a really important meeting," said James Dixon of Dixon Environmental Consulting, who is working with the river associations to study its impacts.

"(Thursday) is the very first time that the general public is going to be able to assemble to offer their take," he said.

At issue is whether Ford Airport's plan to divert runoff from Trout Creek to the Thornapple River goes far enough to ensure damage from the current system does not happen again.

Of particular concern is runoff during winter months, when an organic, airplane deicing solution called propylene glycol is sprayed on aircraft.

The glycol was found to be creating a smelly, filmy buildup in Trout Creek that residents said choked plants and aquatic life of oxygen. What's more, the gushing storm water drastically eroded the creek's banks, residents contend.

Ford Airport is paying out of pocket for the $19 million system, and recent changes to the plans have included a natural filtration system in the mile-long tunnel that will carry runoff from airport grounds to the river.

Brian Ryks, Ford Airport's executive director, said misinformation has been spread about how much deicing solution will be captured and filtered out before it reaches the river.

Now, the airport uses special vacuum trucks that suck up roughly a third of the glycol when it hits pavement at the gate. Another third makes it into the airport's storm water system, and the remaining third remains on the ground.

Once built, the airport's new system will be able to reduce the amount of glycol that hits the river to 7 percent from roughly 36 percent, Ryks said.

"Based on that 7 percent, I feel strongly that that will not result in any adverse impacts to the Thornapple River," he said, "and we'll be monitoring that to ensure that that is not the case."

Airport leaders say the rationale behind diverting runoff to the Thornapple River is the waterway's higher volume will dilute the glycol further. Dixon argued the airport could do more, including building a deicing pad for planes.

He also contended the 7 percent figure only accounts for what glycol makes it into the system. What remains on the ground, he said, is still likely destined to infiltrate the river's watershed.

"Over a third of what they're using, they claim they can't do anything with because it's going to hit the ground surface, it's going to be caught up in the air," Dixon said. "It's still going to vent and be received by the Thornapple River."

Still, Ryks said part of the airport's plan is to continually monitor the system's glycol levels to ensure it is doing its job. What's more, the suggested deicing pad could cost more and would still require some sort of runoff system.

"Community areas need to be maintained and aquatic resources maintained and not harmed," he said. "We will continue to do all we can to improve and help protect water quality, the aquatic life and the natural beauty of the Thornapple River system."